26 PART | I ITS technology enablers
2.8 Bluetooth
Bluetooth is a widespread communication technology that offers simple and
secure wireless connectivity. It is used by billions of devices worldwide aiming
to replace cables and maintain security in short-range communication. Apart
from this, Bluetooth technology offers ubiquitous access, at low power and
at a low cost. In the automotive industry, Bluetooth technology came as an
enabler for hands-free smartphone usage while driving, whereas in healthcare
Bluetooth glucose-monitoring devices are used by diabetics to monitor blood-
glucose levels. Recently Bluetooth has been employed for intravehicle com-
munications that transmit engine-related information directly to the driver’s
dashboard.
The Car Working Group (CWG) is responsible for the development of new
features that employ Bluetooth technology in vehicles since 2000. The Blue-
tooth Core Specification (https://www.bluetooth.com/specifications/bluetooth-
core-specification/) defines a uniform structure for the devices that use it to
communicate with each other, which is based on the pairing of devices at a first
step and the exchange of data at a second step. Bluetooth global acceptance has
been achieved based on the easiness and reliability of connectivity, which guar-
antees that any Bluetooth device will be able to connect to all other Bluetooth
devices in proximity.
Such short-range connections, among Bluetooth devices, allow creating ad-
hoc networks, which are also known as piconets. Piconets are established auto-
matically as one device enters the radio proximity of the other, which signifi-
cantly simplifies the process of connection and disconnection from a network.
A device can belong to multiple piconets at the same time and can communicate
with up to seven devices within the same piconet, thus increasing the possible
network structures that can be achieved. In several cases it is enough for the
device’s Bluetooth wireless option to be set to “visible” and all other devices in
the area can track it, by following it directly or by collecting information from
nearby access points that connect in a mesh.
Bluetooth technology can transmit both data and voice transmissions, thus
allowing multiple innovative applications to be developed, that combine voice
commands and calls, with data transfer for tracking and data collection and
synchronization.
Although the core specification defines a minimum range of 10 m, manufac-
turers can set their own limits to cover a wider range or to provide a less energy-
consuming (but shorter-ranged) solution. As a result, the Bluetooth range may
vary depending on the application and on the radio class used in each case:
• Class 3 radios—have a range of up to 1 m.
• Class 2 radios—have a range of 10 m and are the most commonly used in
mobile devices.
• Class 1 radios—have a range of 100 m or 300 ft and are usually employed in
industrial applications.